The present invention relates to an arrangement for the storing and metered dispensing of liquids, in particular beverage concentrates, by means of a storage vessel for liquids, at the dispensing opening of which, located at the bottom when in the operating position, there is positioned a dosing chamber/dispensing fixture having input- and output-side discharge openings that can be closed alternately by a sliding control valve displaceable in the dosing-chamber housing.
As an example, these arrangements are preferably used in beverage dispensers, by means of which carbonated water is mixed with beverage concentrates for a refreshment drink. Storage vessels for the beverage concentrates are usually fabricated from a dimensionally stable and gas-tight material, and are shaped like a bottle or cuboid. When installed in a beverage dispenser, these storage vessels are positioned with their discharge opening downward. Attached to this discharge opening is a dosing chamber/dispensing fixture with input- and output-side discharge openings that can be closed alternately by means of a sliding control valve. The liquid (beverage concentrate) flows by gravity from the storage vessel into the dosing chamber/dispensing fixture, when that fixture's input-side discharge opening is opened. When this input-side discharge opening is closed by the sliding control valve and, at the same time, the output-side discharge opening is opened, the liquid--likewise by gravity--emerges from the dosing system, so that the quantity of liquid is essentially determined by the dosing-chamber capacity.
In the prior art dosing chamber/dispensing fixtures, however, leakages between the sliding control valve and the dosing-chamber housing can influence the quantity dispensed in a manner difficult to control. Design of a guideway between the sliding control valve and the dosng-housing, which is as free of gaps as possible to avoid these leakage flows, is highly problematical, since this sliding control valve is supposed to be axially movable with the greatest possible ease inside the dosing-chamber housing, so it can be reliably adjusted, in the form of a solenoid plunger, by an electrically generated magnetic field. This method of adjustment requires no mechanical linkages, so that replacement of the dosing chamber/dispensing fixtures in the beverage dispenser, together with the storage vessels, can be carried out with ease.
It is possible to ventilate the head room of this storage vessel or a buffer space therewithin (DE OS 25 44 671) in order to ensure that the flow of liquid is not hampered by volume-equalizing air counterflows and by the subatmospheric pressure developing. These measures require additional technical effort, yet they have not proven to be advantageous, since the air in the head room of the storage vessel easily escapes therefrom to enter the head room of the storage vessel during the flow of the liquid. In the prior art systems, it has even been found expedient to cause a build-up of subatmospheric pressure in the head room so as to counteract the leakage between the dosing plunger and the wall of the dosing-chamber housing.
Also, for reasons having to do with transport and for ease of handling, it has proven very advantageous to make the storage vessel for beverage concentrates of a material that is dimensionally stable. However, such storage vessels are relatively expensive and troublesome with respect to waste disposal, all the more so since the vessels can be used only once and are then discarded. The convenience of using the storage vessel only once is based on reasons of hygiene, but also because of steps taken to prevent the use of a refilled storage vessel. Precautionary steps are taken by adopting appropriate measures in the area of the dispensing opening of the storage vessel.